Participation in at least 20 days of pulmonary rehabilitation by patients with chronic obstructive pulmonary disease (COPD) resulted in statistically significant improvements in quality of life, perception of health status, functional capacity, dyspnea, and depression, in a retrospective analysis.
Furthermore, improvements were seen regardless of the degree of exercise function, dyspnea, or lung function at baseline, reported lead investigator Praful Schroff.
Current American Thoracic Society and European Respiratory Society guidelines recommend the consideration of pulmonary rehabilitation for patients who have persistent symptoms and activity limitations and for those who are unable to adjust to their illness despite optimal medical management (Am J Respir Critical Care Med. 2013 Oct 15;188[8]:e13-64). Recent research had shown that pulmonary rehabilitation benefits patients with COPD without regard to their level of baseline dyspnea, but the influence of the level of baseline exercise capacity on the benefits of pulmonary rehabilitation had not been systematically studied, wrote Mr. Schroff, the designer of the analysis and a student in the division of pulmonary, allergy, and critical care medicine at the University of Alabama, Birmingham (UAB).
The analysis focused on 229 COPD patients enrolled in the pulmonary rehabilitation program at UAB during 1996-2013, all of whom completed questionnaires both at enrollment and after completion of their respective exercise programs. The mean forced expiratory volume in 1 second (FEV1) percent predicted for the cohort was 46.3%.The researchers used pulmonary function data from tests performed within 2 years of enrollment. Change in quality of life and perception of health status were measured using the 36-item Short Form Health Survey (SF-36), dyspnea was assessed using the San Diego Shortness of Breath Questionnaire (SOBQ), depression was assessed using the Beck Depression Inventory (BDI)-II, and functional capacity was assessed using the 6-minute-walk-distance (6MWD) test. On average, the patients reported clinically significant improvements in most components of the SF-36, including an 11.5-unit, a 16.4-U, and a 12.4-U increase in physical function, social function, and vitality, respectively (P less than .001 for all three). The patients also experienced clinically important improvements in the 6MWD test (increase of 52.4 m; P less than .001) and dyspnea (decrease of 9.1 U in the SOBQ; P less than .001). On average, patients’ depression decreased by 3 U, using the BDI II (P less than .001).
When patients in this study were divided into groups based on various aspects of their health at baseline, the levels of improvements seen by each group in most components of the SF-36, the 6MWD, the SOBQ, and the BDI-II were almost always similar.
“We add to the literature by comparing outcomes across quartiles of baseline exercise capacity and showing that patients benefit independent of underlying functional capacity,” said Mr. Schroff and his colleagues.
A few differences in the outcomes following pulmonary rehabilitation were observed between these baseline characteristics–based groups. When patients were grouped by exercise capacity, for example, those with the lowest baseline exercise capacity (as measured by the 6MWD) experienced the largest incremental improvement in the 6MWD. Additionally, when patients were grouped by dyspnea score, those with the worst baseline dyspnea experienced the greatest reduction in dyspnea. However, those with the lowest lung function made the smallest improvement in the 6MWD. Another of these differences was observed between the patients with the lowest baseline lung function and the patients in the other lung function-based quartiles. Those with the worst lung function made the smallest improvement in the 6MWD, which was 39.0 m, on average. All of these subgroups achieved clinically significant improvements in the 6MWD and SOBQ (Ann Am Thorac Soc. 2017 Jan 1;14[1]:26-32).
Each exercise session included aerobic exercises, resistance training, and breathing techniques. Cardiovascular exercise was prescribed starting at 20-30 minutes of continuous or interval bouts and was gradually increasing until 30-45 minutes of exercise was achieved. Patients also received education sessions lasting 40-60 minutes on understanding their disease, smoking cessation counseling, appropriate use of inhalers, diet and nutrition, and stress management. Subjects with other concurrent chronic respiratory diseases were excluded from the analysis.
The researchers noted that their findings may not be generalizable to patients with disease burdens causing them to drop out of the study. “Although we have previously shown that baseline levels of dyspnea, FEV1, and exercise capacity did not influence dropout rates, this could be a source of bias,” they noted.
“Patients with COPD experienced meaningful improvements in quality of life, dyspnea, exercise capacity, and depression, regardless of baseline lung function, dyspnea, and exercise capacity. Current guidelines should be amended to recommend pulmonary rehabilitation to all patients with COPD, regardless of their baseline level of disease burden,” the analysis’ authors said.
Three of the study’s authors reported receiving grants and other fees or a single grant from various sources. The other authors, including Mr. Schroff, said they had nothing to disclose.